Industrial instrumentation and automation
In instrumentation and automation the drive is small, the envelope is fixed before the motion is designed, and the mechanism is usually asked for a peak it visits constantly and a stall it visits by design. The engineering problem is that peak torque, lost motion and the end-stop condition are decided by three different numbers, none of which is the continuous rating that catalogs are sorted by. A gripper stalls on every cycle. A valve stalls at every close. An inspection turret is specified in arcseconds against a train with degrees of backlash.
The clusters
Mechanisms that share a load model, not markets that share a trade show.
- Semiconductor and optical inspection
- Print and labeling mechanisms
- Surface measurement and metrology
- Compact conveyors, indexing, grippers and end effectors
- Small valves and dampers
Each of these issues is a different physical quantity wearing the same word.
The middle column is what the issue actually is. The right column is where it gets decided, which is usually earlier than the motor selection.
| Issue | What it actually is | Where it is decided |
|---|---|---|
| Envelope | Usually fixed before the motion is designed, which removes most of the catalog before anything is calculated. | Body diameter and total length, including the gearhead and any feedback. |
| Torque margin | Peak against the gearhead rating, not continuous against the continuous rating. | The acceleration or breakaway case, whichever is larger. |
| Backlash | The dominant term in almost every positioning budget on these mechanisms. | Stage count, and whether the approach can be unidirectional. |
| Dynamic response | Reflected inertia against rotor inertia, and the settling time at the tool point. | Ratio, drive radius, and the moving mass. |
| Encoder fit | The reviewed catalog holds one published feedback record with a fit to one platform. | A configured assembly in most cases, which has to be known early. |
| Duty cycle | Almost always intermittent, which makes the continuous rating close to irrelevant. | RMS torque over the real period, dwell included. |
| Lead time | The gap between a working prototype and a released configuration. | Sample status and the configured release path, stated per configuration. |
| Customization | Shaft, mounting, lead, connector, winding and ratio, most of which are configuration rather than design. | A review that establishes which of them are actually required. |
Four roles, four different questions
A product page and a project record have to serve all four without becoming four separate websites. What each one needs before they will make contact is not the same information.
| Role | What it needs before contact | What it converts on |
|---|---|---|
| Mechanical engineer | Envelope, shaft and mounting, torque and speed at the real operating point, load model, life definition, noise. | A saved candidate, CAD, a drawing, or an application review. |
| Electrical or controls engineer | Voltage, current at the operating point, the torque-speed characteristic, driver requirements, feedback fit, thermal margin. | A curve, a calculation, or a feedback and control review. |
| Sourcing or procurement | Availability, sample status, minimum order, lead-time band, origin, cost drivers, and a second-source path. | A cross-reference, a supply-chain review, or a volume quotation. |
| Quality or reliability | Variation, life evidence, traceability, failure modes, and how change is controlled. | A failure analysis, a qualification plan, or a test report. |
The applications in this wedge
4 of the 10 pages in the library. Each one is a load model with the arithmetic shown.
Published configurations whose gearhead is rated at or above 196 mN·m at the output, which is the band a stalling mechanism needs.
17 of 32 published configurations. Continuous output torque is calculated from the motor's rated torque through the ratio and the typical stage efficiency. The gearhead limit is a maximum, not an operating point, and 29 of 32 published configurations can stall above it.
| Configuration | Class | Diameter | Ratio | Rated output speed | Continuous output torque | Gearhead limit |
|---|---|---|---|---|---|---|
| MM-B2419-P03610-120A | Brushless DC | 24.2 mm | 361:1 | 14.4 rpm | 304.3 mN·m | 785 mN·m |
| MM-C1736-P02560-060B | Coreless brushed DC | 22 mm | 256:1 | 14.5 rpm | 319.2 mN·m | 785 mN·m |
| MM-C1837-P00903-120D | Coreless brushed DC | 22 mm | 90.25:1 | 93.1 rpm | 234.4 mN·m | 588 mN·m |
| MM-C2137-P00903-120C | Coreless brushed DC | 22 mm | 90.25:1 | 19.7 rpm | 234.4 mN·m | 588 mN·m |
| MM-C2432-P00760-090A | Coreless brushed DC | 24 mm | 76:1 | 109.5 rpm | 236.8 mN·m | 588 mN·m |
| MM-C1626-P04552-240A | Coreless brushed DC | 16 mm | 455.19:1 | 23.5 rpm | 191.8 mN·m | 490 mN·m |
| MM-C1636-P04552-240A | Coreless brushed DC | 16 mm | 455.19:1 | 24.4 rpm | 191.8 mN·m | 490 mN·m |
| MM-C1726-P01575-120A | Coreless brushed DC | 17 mm | 157.46:1 | 36.9 rpm | 150.2 mN·m | 392 mN·m |
| MM-C1837-P00226-240C | Coreless brushed DC | 22 mm | 22.56:1 | 359.9 rpm | 87.6 mN·m | 392 mN·m |
| MM-C2137-P00226-240C | Coreless brushed DC | 22 mm | 22.56:1 | 291.7 rpm | 124.2 mN·m | 392 mN·m |
| MM-C2432-P00190-240A | Coreless brushed DC | 24 mm | 19:1 | 401.6 rpm | 160.5 mN·m | 392 mN·m |
| MM-C1321-P03661-030A | Coreless brushed DC | 13 mm | 366.12:1 | 16.7 rpm | 120.8 mN·m | 294 mN·m |
| MM-C1329-P00777-120C | Coreless brushed DC | 13 mm | 77.66:1 | 123.6 rpm | 113.4 mN·m | 294 mN·m |
| MM-C1736-P00292-240C | Coreless brushed DC | 17 mm | 29.16:1 | 192 rpm | 84.7 mN·m | 294 mN·m |
| MM-B2419-S00325-240A | Brushless DC | 37 mm | 32.5:1 | 212.3 rpm | 58.1 mN·m | 196 mN·m |
| MM-C1321-P00191-060B | Coreless brushed DC | 13 mm | 19.13:1 | 404.6 rpm | 15.5 mN·m | 196 mN·m |
| MM-C1329-P00191-120B | Coreless brushed DC | 13 mm | 19.13:1 | 417.7 rpm | 23.2 mN·m | 196 mN·m |
The reviews that apply here
One of these is usually the right first move. All of them return engineering, not a quotation.